Sealed bearing with axially undulating seal lip

ABSTRACT

A sealed ball bearing for sealing the annular space between the inner and outer races includes a flexible elastomeric washer that is held in place by a retaining ring mounted in a groove on the outer race. The retaining ring has a plurality of radially inwardly directed spring fingers which urge local segments of the washer axially into contact with the ribbon separator of the bearing thereby causing the washer to assume an axially undulating contact pattern with the inner race. When the bearing is rotated, the separator acts in a camming fashion to axially displace the local segments to establish a traveling wave motion in the washer which prevents contaminant buildup.

[45:1 Aug. 14, 1973 SEALED BEARING WITH AXIALLY don, Pg. 54-67.

UNDULATING SEAL LIP Primary Eiaminer-Charles J. Myhre Assistant Exarnjgrk. H- Lazarus Attorney-J L Carpenter an d IPeter D. Sachtjen [75]Inventor: Charles N. Hay, Sandusky, Ohio [73] Assignee: General MotorsCorporation,

Detroit, Mich.

[57] ABSTRACT A sealed ball bearing for sealing the annular space be-[22] Filed: May 15, 1972 21 Appl. No; 253,041

tween the inner and outer races includes a flexible elastomeric washerthat is held in place by a retaining ring [52] US. 308/1872, BOB/187.1

mounted in a groove on the outer race. The retaining Int. Cltn..." h aof radially directed spring [58] Field of 308/1872, 187.1, fingers whichurge local segments ofthe washer axially 308/187 into contact with theribbon separator of the bearing thereby causing the washer to assume anaxially undu- [56] References Cited UNITED STATES PATENTS 12/1965 latingcontact pattern with the inner race. When the bearing is rotated, theseparator acts in a camming fashion to axially displace the localsegments to establish a traveling wave motion in the washer whichprevents contaminant buildup.

OTHER PUBLICATIONS Product Engineering, Feb. 29, 1960, Wayne W. Gor- 2Claims, 5 Drawing Figures v Summinwake SEALED BEARING WITH AXIALLYUNDULATING SEAL LIP The present invention relates to sealed bearingsand, in particular, to a sealed ball bearing having positivedisplacement means for preventing the buildup of contaminants at theentrance to the lubricant chamber.

Antifriction bearings, such as ball bearings, oftentimes are providedwith shields and seals that prevent the outward flow of the bearinglubricant and effect a barrier against the ingress of contaminants. Acommonly employed design takes the form ofa metal shield which issnapped into an annular groove of the outer race. The space between theshield and the inner race establishes a labrynth which limits outwardflow of lubricants and inward migration of contaminants. A more positiveseal can be obtained by molding an elastomeric seal lip at the innerperiphery of the shield that effects a sealing contact with the outersurface of the inner race. This arrangement has proven to be highlyeffective in most sealed bearing environments; However, in many lowspeed applications such as an agriculture and earth-moving machinery,which are operated in severely contaminated areas, contaminants canbuild up adjacent the sealing interface and eventually work their wayunder the seal lip to the interior of the bearing. Such innercontamination can cause scoring and other damageto the bearing membersand the raceways. I j

The present invention provides a sealed bearing having positive meansfor axially displacing contaminants away from the interface duringdynamic operation. Such a bearing uses the camming action of a ballbearing ribbon separator acting against an elastomerical sealing washerto impart a traveling wave motion to the seal lip. More particularly,the separator normally includes circumferentially alternating series ofarcuate axially projecting humps and inwardly spaced flats or lands.Herein, a sealing washer and a retaining spring are commonly disposed ina groove in the outer race closely adjacent to the separator. Theretaining spring includes axially and radially inwardly projectingspring fingers which serve to bias local segments of the washer againstthe humps and between the lands. This biasing distorts the washer into acircumferentially axially undulating contact pattern. As the bearing andthe separator rotate, each local segment of the washer will alternatelyrise and fall in accordance with the profile of the separator. Thus, asa section of washer contacts one of the arcuate humps, it will graduallybe axially displaced outwardly against the biasing of the spring fingeruntil reaching the crest of the hump and will thereafter be biasedinwardly toward the adjacent land. This alternate rise and fall motionof the washer serves to axially displace any contaminants tending toaccumulate at the sealing interface.

The above and other features of the present invention will be apparentto one skilled in the art upon reading the following detaileddescription, reference being made to the accompanying drawingsillustrating a preferred embodiment of the present invention in which:

FIG. 1 is a cross sectional view of sealed bearing with an axiallyundulating seal assembly made in accordance with the present invention;

FIG. 2 is an enlarged sectional view of the bearing shown in FIG. 1illustrating the operative relationship between the bearing separatorand the sealing washer;

FIG. 3 is a view taken along line 33 of FIG. 1 showing details of theretaining ring;

FIG. 4 is a developed view taken along line 44 of FIG. 3;

FIG. 5 is a view illustrating the contact pattern between the inner raceand the seal lip.

Referring to the drawings, there is shown an antifriction bearing havingan inner race 12 and an outer race 14. The races 12 and 14 arerespectively provided with mutually facing annular raceways I6 and 18.The raceways 16, 18 receive a plurality of spherical balls 20 which arecircumferentially spaced and guided by a bearing cage or ribbonseparator 22 for precision coaxial antifriction rotation between theraces 12 and 14. The mutually facing annular surfaces of the races 12and 14 define an annular chamber 23 which is sealed by a seal assembly24. The separator 22 comprises a pair of separator rings 25, 26 whichare stamped from sheet material and preferably include an innercushioning layer 28.

As shown in FIG. 4, the separator rings 25, 26 and ring 25 inparticular, include a series of flats or lands which are mutuallyseparated by arcuate humps 32. The separator rings 25, 26 are fastenedtogether at the flats 30 by rivets 34. The mutually facing surfaces ofthe humps 32 define pockets 36 for the reception of the balls 20. In theillustrated separator, these ball pockets 36 are both circumferentiallyand radially curved to provide spherical pocket walls for retaining theballs 20 in unit handling relation. With this construction, theseparator 22 is supported by the balls 20 out of engagement with theracesl2 and 14.

The seal assembly 24 is retained. in an annular groove 38 formed in theinner surface of the outer race 14. In this connection, it should benoted that asecond seal assembly could be retained in a correspondinggroove on the righthand side of the outer race 14. The seal as sembly 24comprises an elastomeric sealing washer 40 and a retaining spring 42.The washer 40 in the free form comprises a flat annulus having an outerdiameter substantially the same as the diameter of the groove 38 and aninner diameter having an interference fit with the outer surface of theinner race 12. Thus, in assembly, the interference will cause an axialflattening or deforming at the sealing interface with the inner race 12to form an axially curved annular seal lip 44.

Referring to FIGS. 3 and 4, the retaining spring 42 includes an annularouter body 48 which is received in the groove 38 and a plurality ofcircumferentially spaced, radially inwardly projecting spring fingers50. The spring fingers 50 are axially inwardly curved toward theinterior of the bearing chamber 23. Thus, the spring fingers 50 willaxially bias first local segments 52 of the washer 40 against the facingsurface of the humps 32 and second local segments between the humps 32inwardly toward the lands 30. In the preferred embodiment wherein thenumber of spring fingers 50 equals the number of lands and humps 32, thebiasing provided thereby urges the seal washer 40 into an axiallyundulating sinusoidal pattern. Thus, as shown in FIG. 5, the seal lip 44will have a ribbon like contact pattern comprising crests 56corresponding to the humps 32 and valleys 58 corresponding to the lands30.

During dynamicoperation, the separator 22 rotates at one-half the speedof the outer race 14 and the seal assembly 24. The difference inrelative speeds between the seal assembly 24 and the separator 22 causesthe separator ring 25 to impart a camming action to the sealing washer40 which in turn imparts a traveling wave motion to the seal lip 44.Thus, as spring finger 50 advances toward the hump 32, the latter willtend to cam the associated spring finger 50 and adjacent washer sectionaxially outward in accordance with its changing axial profile. Thiscauses an axial displacement of the radially corresponding segment ofthe seal lip 44. Thus, any particulates or contaminants A, will bedisplaced axially outwardly as indicated by arrow B. This will keep theinterface clear from the contaminants which would otherwise enter thechamber 23. I

When the spring finger 50 and the crest of'the hump 32 are aligned, themaximum rise of the camming action has been reached and upon furtherrelative rotation between the washer 40 and the separator 22, the springfinger 50 will urge the local segment of the washer 40 axially inwardlytoward the lands 30 in accordance with the changing profile of theseparator ring 25 and consequently change the contact pattern tocorrespond with the valleys 58.

It will be appreciated, of course, that a change in the relative numberof spring fingers with regard to the number of balls and changes in theinitial curvature of the spring fingers 50 will cause the seal lip 44 toassume a slightly different contact pattern. However, regardless ofthese changes, the inherent camming action provided by the separatoragainst the washer will cause a migratory axial oscillation of the seallip which will prevent the buildup of contaminants thereat. It will alsobe appreciated that the biasing action provided by the separateretaining ring can be integrally accomplished by suitable change in thecross sectional area and molded shape of the washer.

Although only one form of this invention has been shown and described,other forms will be readily apparent to those skilled in the art.Therefore, it is not intended to limit the scope of this invention bythe embodiment selected for the purpose of this disclosure but only bythe claims which follow.

What is claimed is:

l. A sealed bearing comprising: a pair of relatively rotatable racemeans; rolling elements between said race means; a separator for spacingsaid rolling elements, said separator including a pair of annularmembers having circumferentially alternating lands and outwardlyprojecting curved portions, said curved portions defining therebetweenpockets for guidingly retaining said rolling elements; a seal membercarried by one of said race means having an annular sealing surfaceengaging the other of said race means; biasing means operativelyassociated with said seal member for locally urging sections thereofagainst and between said curved portions such that said sealing surfaceassumes a circumferentially undulating ocntact pattern with said otherof said race means whereby relatively rotating said race means causessaid curved portions of the separator to axially displace said sectionsin a traveling wave motion to displace materials away from said sealingsurface.

2. A sealed ball bearing comprising: an inner race and an outer racerelatively rotatable about an axis; a plurality of balls engaging saidraces for providing antifriction rotation between the races; a separatorfor circumferentially spacing said balls, said separator having a pairof annular rings having mutually facing outwardly projecting arcuateportions defining pockets for guidingly retaining said balls, saidarcuate portions being separated by axially recessed flat lands; anelastomeric seal member carried by said outer race having an annularseal lip engaging said inner race; a spring them her carried on theouter race, said spring member having a plurality of radially inwardlyextending fingers for locally urging portions of said seal memberagainst said arcuate portions whereby said seal lip assumes acircumferentially undulating contact pattern with said inner racewhereby rotating said race means causes a camming action of said arcuateportions against the biasing of the spring fingers to axially displacethe seal lip in a traveling wave motion and prevent contaminant buildupat the sealing surface.

1. A sealed bearing comprising: a pair of relatively rotatable racemeans; rolling elements between said race means; a separator for spacingsaid rolling elements, said separator including a pair of annularmembers having circumferentially alternating lands and outwardlyprojecting curved portions, said curved portions defining therebetweenpockets for guidingly retaining said rolling elements; a seal membercarried by one of said race means having an annular sealing surfaceengaging the other of said race means; biasing means operativelyassociated with said seal member for locally urging sections thereofagainst and between said curved portions such that said sealing surfaceassumes a circumferentially undulating ocntact pattern with said otherof said race means whereby relatively rotating said race means causessaid curved portions of the separator to axially displace said sectionsin a traveling wave motion to displace materials away from said sealingsurface.
 2. A sealed ball bearing comprising: an inner race and an outerrace relatively rotatable about an axis; a plurality of balls engagingsaid races for providing anti-friction rotation between the races; aseparator for circumferentially spacing said balls, said separatorhaving a pair of annular rings having mutually facing outwardlyprojecting arcuate portions defining pockets for guidingly retainingsaid balls, said arcuate portions being separated by axially recessedflat lands; an elastomeric seal member carried by said outer race havingan annular seal lip engaging said inner race; a spring member carried onthe outer race, said spring member having a plurality of radiallyinwardly extending fingers for locally urging portions of said sealmember against said arcuate portions whereby saiD seal lip assumes acircumferentially undulating contact pattern with said inner racewhereby rotating said race means causes a camming action of said arcuateportions against the biasing of the spring fingers to axially displacethe seal lip in a traveling wave motion and prevent contaminant buildupat the sealing surface.